Hydraulic-pressure-measuring apparatus.



No. 895,991. PATENTED AUG.11 1908.

, A. H. EMERY.

HYDRAULIC PRESSURE MEASURING APPARATUS.

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HYDRAULIC PRESSURE MEASURING APPARATUS.

APPLICATION PILED AUG. 6,1906.

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No. 895,991. PATENTED AUG. 11, 1908. A. H. EMERY. HYDRAULIC PRESSUREMEASURING APPARATUS.

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APPLICATION FILED AUG. 6,1906.

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APPLICATION FILED AUG. 6 1906.

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. E A W/ W No. 895,991. PATENTED AUG. 11, 1908.

A. H. EMERY. 9 HYDRAULIC PRESSURE MEASURING APPARATUS.

APPLICATION FILED AUG 6,1906.

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UNITED STATES PATENT onsron.

ALBERT H. EMERY, OF STAMFORD, CONNECTICUT.-

HYDRAULIC-PRESSURE-MEASURING APPARATUS.

Specification of Letters Patent.

Patented Aug. 1 1, 1908.

Application filed. August 6, 1906. Serial No. 329,440.

havehere shown it applied to a car dynamometer shown in 19 figures ofthe drawings in which:

Figure 1 shows a plan of a car dynamometer assembled to the frame-workof the car;

Fig. 2 shows a side elevation of the dynamometer and part of theframework of the car, some parts being in section; Fig. 3 shows a planof one-half of the main press of the dynamometer attached to theframework of the car Fig. 4 is a sectional view of the main press of thedynamometer and some of the car frame, showing a coupling which couplesthe piston rod of the press to an extension of the draw-bar, andshowingthe pipe leading to the measuring and recording part of thedynamometer. The valvesand pipes shown in the upper part of the view arebehind the general plane of the section, while the valves shown in thelower half are actually opposite those in the upper part of the cylinderand in front of the general plane of the section.

Figs. 5, 6, 7 and 8 show these valves to a larger scale. Fig. 5 shows asection of part of the main press, cylinder and piston, and of thevalves and pipe connecting with the measuring and recording cylinder ofthe dynamometer, with the piston in a central position; Fig. 6 shows asection of part of the main press, cylinder and piston and of the valvesconnecting the supply-tank, with the piston in a central position; Fig.7 is similar to Fig. 5, but shows the piston moved away from the centralposition, and the valves, one

- closed and the other open; Fig. 8 is similar to Fig. 6, but with thepiston moved away from its central position, and the valves, one openand the other closed; Fig. 9 shows a longitudinal section of themeasuring and recording part of the dynamometer; Figs. 10, 11 and 12show cross-sections of the measuring and recording part of the dynamom=eter, with some of the parts removed, the sec- I tions being taken onlines a a, l) b, and c c, Fig.

9, respectively; Fig. 13 shows a side elevation of some of the pistonsand part of the arbor which works in the cylinder of the measuring andrecording part of the dynamometer; Figs. 14 and 15 are views of some ofthe pistons, showing methods of grooving; Fig. 16 shows in section aportion of one of the bushings (see Fig. 4) around the main piston rodin the main press cylinder, and

shows the form of grooving; and Fig. 17 1 shows the section of a chamberthrough which the liquid passes in going from the main press to themeasuring and recording cylinder. This chamber is inclosed in another,to be used in cooling the li uid, if nec- 'essary. Fig. 18 shows an ende ovation of the housing and many of the principal parts. Fig. 19 showsaside elevation of one of the rockingsupports, which support the pistonrod and piston on a spring-supported bar, and

also shows some of the parts adjacent thereto.

In the figures: 1 are plates running lengthwise of the car, from end toend, forming the sides of a box girder, of which plates 2 and 3 form artof the top and bottom, at either end of a centrally reinforced portionof this girder, which portion contains the main hydraulic press of thedynamometer.

4 and 5 are the bottom plates of this reinforced portion.

6, 7 and 8 are cross members in the girder. 6 and 8 form the ends of thereinforced portion.

9 are two longitudinal plates riveted to 1, 6, 7 and 8, reinforcing 1,and 10 are plates riveted to 1 and 9, on each of which a ledge is laned,on which rest the main housin 11 bolted to these. plates 10 by bolts 12.his housing transmits all the load from the drawbar to the frame of thecar.

13 is a portion of the drawbar and has on it shoulder 13 and collar 14,which limit its motion in either direction by striking bosses on crossmember 8. The load in either direction on the drawbar 1 3 is transmittedthrough i the initially loaded springs 15 to the main piston rod 16which carries on it a piston 17,

old in place by sleeve 18 and sleeve nut 19. This iston 17 closely fitsinto the two-part cylin er 20, which is held securely in position by thehousing 11 and stud-bolts 11, and longitudinal loads on the piston rod16 are transmitted to the liquid between the piston and one head of thecylinder 20 and so to the housing 11 and car body,'the liquid underpressure passing through one of the valves 21 to the pipe 22 which leadsto. the measuring and recording part 'of the machine. Bolts 23 hold thetwo halves of the cylinder together and two spring bars 24 carry theweight of the cylinder and iston in assembling. They are secured to t ecylinder 20 by two horizontal screws ineach, as shown in plan andelevation, but not numbered. These bars 24 and cylinder 20, to whichthey are attached, are supported by four vertical screws 24, two in eachbar; shown in plan in Fig. 3 and elevation in Fig. 18 at the ends of thebars. These screws rest on the housing 11, and are screwed down untilthe deflected bars raise the cylinder until its axis is exactly in linewith the axis in the hole in the housing so the'weight of the cylinderwill not come on the bushings 26 and distort them.

25 are bushings in' the half-cylinders and 26 are similar bushings whichextend through the cross-pieces of the housin into the cylinder andcenter the cylinder with the housing. These bushings are best made ofbronze.

27 are bars bolted to the under side of the housing 11 and carry trackbar 28 by rods 29 and springs 30.

-31 are collars on the piston rod 16 and sleeve nut 19, and 32 are axlesrunning roller bearings 33 in these collars 31.

.34 are rocking supports on axles 32, and

they rest and roll on track bar 28,- as the piston moves backwards andforwards, so that the weight of the piston rod 16 and attached parts,instead of resting upon the bushings 25 and 26 is substantially carriedon the roller bearings and the friction and wear thus greatly reduced.

qles 35, Fig. 5, lead to the pipe 22, whic eads to the measurin andrecording end of the dynamometer,'w ile nipples 36,

Fig. 6, lead to a similar pipe, which leads to supply tank. Valves '21seat in the two halves of the cylinder, and each is held against itsseat or with its stem against the piston 17 by spring 37 working againstcap 38," the valves being guided by their cases 39. Valves 40 seat'intheir cases 41 which screw into the halves of the cylinder, and thesevalves close the passage leadin from the cylinder to the sup ly tank,which is not .shown but which is ocated in a convenient position abovethe axis of the recording cylinder. Valve stems 42 have flanges on theirends which hook onto a flange on rings 43 0 en, and valve 40, on thatside closes; thus, a

t e side of the piston which has approached its cylinder head is open tothe recording cylinder of the dynamometer and closed to the supply-tank,and the other side of the piston is open to the supply-tank and closedto the recording-cylinder. The osition of all these valves is reversedwhen t e piston moves to the left. With these arrangements of thevalves, a constant portion of the load on the piston in either dlrectionis always transmitted to the measuring and recording cylinder, thatportion being the ratio of the acting area of the main press piston tothe area of the recording cylinder. 4

Pipe 22 leads from the two-part cylinder 20 to the chamber 46, and pipe47 leads to elbow 48 in which is screwed nipple 49, which also screwsinto cylinder head 50. (See Fi 2.) Recording cylinder 51 is supported bybracket 52 at one end, and is fastened .to bracket 53by its head 54 andnut 55 at the other. These brackets 52'and 53 are bolted to table top 56by bolts 57, and 56 is four close fitting pistons 65.

ress cylinder 20 and the re-- The main cordin cylin er 51 are each verycarefully groun and lapped true, and the pistons to work therein verycarefully ground and lapped to'fit closely therein. They must not be sotight as to give much friction, but to avoid leakage, the clearance isvery small and the weight of the iston or imperfections of the work willusua y cause the clearance to be more on one side than on the other andthe liquid under pressure flows more rapidly into the greater clearance,causing a thrust of the piston against the side of the cylinder oppositethe greater clearance, which thrust causes friction and wear and bringserror into the measurements. To avoid this sidepressure, the clearanceshould be kept uniform on all sides, so that the fluid pressure will beuniform all around the piston. This may be very perfectly accomplishedby the use of spiral grooves which are clearly shown in Figs. 13 to 15inclusive. These balancing'grooves may be placed on the interior of thecylinder, as shown on piece No. 25 (see Figs. 4 and 16). The pistons 65are provided with these exterior spiral grooves which may run from oneend to the other, as shown on piston 65, Fig. 13,

' shown on 65", Fig. 14.

' forming a or which may start in a circular groove near one end and runto the other end, as seen on 65, Fig. 13. The part which is not groovedmay be very slightly conical, tapering towards the end of the piston.This taper is not enough to show on the drawing. The spiral groove mayconnect two circular grooves, one near either end of the piston, as Thepiston will be more perfectly balanced by having one or more pairs ofspiral grooves, the two grooves air, starting diametrically opposite toeac other. A piston with one pair is shown in 65, Fig. 1-5. The mainpiston 17 is also provided with these spiral grooves which are not shownin the drawing. These pistons 65 are placed on the ends of arbor 64, andheld in place by collar 66 and nut 67. Sleeve 65 may be removed fromthis arbor and pistons substituted therefor, to further reduce theleakage. Wheels 68 have axles running in bushings 69 in side bar 70, andcarry the weight of the pistons and arbor through the springs 71 and 72,working between side bars 70 and cross-pieces 73, which are fastened tothe top face of the arbor. These springs enable the wheels to carry theweight of the arbor, etc., and reduce the friction and wear by nearlyequalizing it around the cylinder.

Piston rod 74 is screwed into nut 75, and against the end of the arbor64, at one end, and slips-into the piece 76 at the other. Piece 76 whichfits in the hole in crosshead 78 is secured in place by.nut 79, whichcarries rod 81, which carries the pen for making the record on the apermoving over the papertable 61. This crosshead 78 is fastened tocrosshead 82 by four shouldered bars 83 and nuts 84, the bars passingthrough clearance holes in bracket 53; all forming a truck which iscarried by wheels 85 on shafts 86, the shafts running in ball bearingsin brackets 87, fastened to crossheads 78 and 82. Wheels 85 roll ontrack bars 62 and carry the weight of the truck and attached arts, whilesimilar wheels 88 carry any si e load that may occur Helical compressionsprings 89 and 90 are fastened at one end to bracket 53 and at-the otherto-crosshead 82 which moves with the piston 65, and these springs resistthe motion nuts 96. Thus, normally,

of the crosshead, and thus the motion of the pistons; and as all theload on the pistons is transmitted to these springs, the amount of theircompression is a measure of that load.

91 are initially loaded bufier springs acting between'the bracket 52 andring 92, being held in place by ieces 93 and 94, their load being heldby t e shouldered bars 95 and they simply hold these bars 95 against thebracket 52. Long rods 97 screw into bars 95 and' project through crosshead 82 and have enlarged heads against which crosshead 82 strikes whenit reaches a desired amount of motion, and its further motion is thenresisted by bufler springs 91, as Well as by the measuring springs 89and 90. These measuring springs 89 and 90 may be of any suitable form oftension or compression springs of uniform rate fastened so as to resistthe motion of the pistons, but are preferably compression springs havingnearly rectangular section made -by taking a s iral cut through the wallof a hollow cylin er, from near one end nearly to the other, leaving asolid ring of metal at each end. Should a pair of these springs 89 or 90give too little resistance, a supplementary spring 98 may be used, whichspring is fastened to crosshead 53 and to su port 99, which is securedto bracket 52. T is spring increases the rate of the measuring springsby the desired amount. The measuring springs 89 or 90 are made in pairs,one right and one left, and one or more airs are used at a time to givethe desired va ue to the pressure ordinates, corresponding to themovements of the pistons.

Pieces 100 and 101, Fig. 17, form the heads of the tank 46 and inconjunction with piece 102 form an inner chamber through which theliquid passes on the way from the main press to the recording cylinder.The heads 100 and 101 are securely held against the ends of the pieces46 and 102 by bolts 103 and nuts 104. This tank 46 is held in place bypipe 105 and bolt 106. Plugs 107, close the openin s into the outerchamber and by replacing t em with pipes, liquid can be circulated intothis outer chamber to cool or warm the contents of the inner chamber. Avalve 108 is used to cut oil the flow of the liquid from the main pressto the recording 0 inder, but is open when the dynamometer is in use,and it is used to throttle the flow of the liquid and thus preventunduly rapid motion of the recording apparatus. Plug valves 109 allowthe liquid to be drawn from the inner chamber at any time, withoutdisturbing the rest of the apparatus.

Having thus described-my invention, what I claim and desire to secure byLetters Patent is: H

1. In a-dynamometer, in'combination with the housing, the cylinder, andpiston contained in said cylinder, the bars 24 and adjusting screws 24in the ends thereof, supporting the cylinder and its contained piston insaid housing.

- 2. In a dynamometer, the combination with a housing, and the containedcylinder, of the bushings 26 centered in the two ends of the housing androjecting into the cyhnder, securely fixing tfie axis of the cylindercentral with the holes bored in the housing for these bushings. V

3. In a dynamometer, the combination With a housing, and its containedcylinder,

piston, and piston rod, and outer bushings 26 which establishescommunication between v theo difierent points on said surface, and tendsto equalize at diametrically opposite points, ressure due to leakage ofthe pressure-fluid etween the surfaces.

5. In a hydraulic measuring a paratus, a pressure piston constructed wita pair of equidistant, fine, spiral grooves, starting at diametricallyopposite points in a plane normal to the axis of the piston andextending at the same pitch around a ortion of its exterior, and tendingto equalize at diametrically opposite points, the pressure of theliquidleaking around the piston.

6. In a hydraulic measuring apparatus, a pressure piston constructedwith a circular groove near one end thereof and a fine, slpiral groovearound a portion of its exterior eading from the circular groove andtending toequalize at diametrically opposite points, the pressure of theliquid leaking around the piston.

7 In a hydraulic measuringapparatus, a pressure piston constructed witha air of circular grooves near the ends thereo and a fine spiral grooveconnecting said circular grooves for the pur ose set forth.

8. In a ydraulic measuring apparatus, a

pressure piston constructed with a circular groove near one end and apair of diametrically opposite fine spiral grooves leading from saidcircular groove and extending toward osite end of the piston. I 9. n ahydraulic measuring apparatus, a pressure piston constructed with a pairof circular grooves near the ends thereof and a pair of diametricallyopposite fine spiral grooves connecting said circular grooves.

10. Ina hydraulic measuring-apparatus, the combination with the ressurepiston rod, of the bushing surrounding said piston rod constructed witha fine spiral groove on its interior, for the urpose set forth.

' 11. In a hydrau lic measuring apparatus, the combination of thecylinder, the pressure piston and piston rod working therein, a rollingsupport for said piston and piston rod, and means for carryingthe weightof said piston and rod, through the rolling support.

12. In a hydraulic measuring apparatus, the combination with a cylinder,a piston, a piston rod, and a rolling sector 34; of a bar 28, andsprings 30 to carry the Wei ht of'the iston, piston rod and partscarrief thereby,

or the urpose set forth.

13. n a dynamometer car, a large rectan- 'gular box below the floor ofsaid car, forming 'said passage.

part of the main girder of the car, in combination with the cylinderhousing and the Weighing cylinder of the dynamometer as explained.

14. In a hydraulic measuring apparatus, the combination with thecylinder, and its contained piston, of a valve 40, a rod 42, connectedto the piston and adapted to engage the valve in the direction ofunseating, a spring 45 through which said rod moves the valve in thedirection of seating, whereby, when the piston is on one side of acertain position the valve remains closed through the action of thespring and iston, and when the piston is on the other si e, of thiscertain position, the valve is positively held open by the pistonthrough said rod.

15. In a hydraulic measuring ap aratus, the combination with a cylinder,and its contained iston of a pair of valves 40, passages contro ed bysaid valves, and connections between said valves and the piston,comprising rods 42 connected with the piston and adapted to engage thevalves in the direction of unseating, and springs through which the.

rods are ada ted to move the valves in the directions 0 their seating;the lengths 'of these connections bein such that at one part of thestroke of the 1ston, both valves are held open and at a other parts ofsaid stroke, one valve is held open and the other held closed,substantially as explained.

16. In a hydraulic measuring ap aratus,

the combination with a cylinder, an its contalned piston, of a pair ofinlet valves 40, a

pair of outlet valves 21 and means through which all of said valves'are'held open by piston at one part of its stroke, as and for the purposesexp ained. V

17. In a ydraulic measuring apparatus, the combination with therecordlng cylinder,

and the main weighing cylinder connected therewith; of an interposedsettling tank through which the liquid passes on its way from one ofsaid'cylinders to the other 18; In a railway-car dynamo meter, thecombination with the weighing-cylinder and the recording cylinderconnected therewith;

of a throttling valveinte osed in the connection between said cylin ersto prevent too rapid flow .of liquid through said passage.

19. In a 'h. draulic' measurin apparatus, the combinatlon with therecording cylinder,

and the main weighing cylinder connected therewith; of an interposedsettling tank through which the liquid passes on its way from one ofsaid cylinders to the other; one

head of said tank containing the passage leading from the main cylinderinto this tank and supporting a'valve'to throttle or close 20. In a hdraulic measurin apparatus,

the combination with the recording cylinder, I

and the main :weighing cylinder connected thereto; of an interposed tankthrough which 13 the liquid passes on its way from one cylinder to theother, and means for regulating the temperature of liquid in said tank.

21. In combination with a pressure indicating cylinder, two groups ofpistons, and a common piston rod by which said pistons are carried; saidroups of pistons being separated a suitabIe distance, to better supportand guide the rod which transmits the pressure on the pistons to theindicating apparatus.

22. In a hydraulic measuring apparatus, the combination with a cylinderand its contained pistons and piston rod; of wheels for carrying theweight of said pistons and piston rod, said wheels being placed betweenthe pistons and rolling in said cylinder.

' 23. In a hydraulic measuring apparatus, the combination With acylinder and its contained pistons and piston rod; of Wheels rolling insaid cylinder, for carrying the weight of said pistons and piston rod,and spring supported bearings for said wheels.

4 24. In a hydraulic measuring apparatus, the combination of a recordingcylinder, a piston, a'piston rod, a fixed abutment, a pair of movingcross-heads driven by the piston and rods connecting said cross-heads,and a resisting spring between the fixed abutment and one of the movingcross-heads.

25. In a hydraulic measuring ap aratus,

the combination of a recording cylin er 51, a piston rod with a piston,a fixed abutment 53, a moving cross-head 78 connected to said pistonrod, a moving cross-head 82 connected to the cross-head 78 by rods 83;and a air of compression springs between the fixe abutment 53, and themoving cross-head 82, to balance and measure the pressure on thepistons.

26. In a hydraulic measuring apparatus, the combination of a recordingcylin er 51, a piston rod, a piston, a fixed abutment 53, movingcross-head 78 connected to said piston rod, and a movin cross-head 82connected to the cross-head 78 by rods 83, a pair of compression springsbetween the fixed abutment 53 and a moving cross-head 82, to balance andmeasure the pressure on the piston, said springs being rigidly fixed attheir ends to the abutment 53 and to the moving cross-heads 82,respectively.

The foregoing specification signed at Stam ford this seventeenth day ofJuly, 1906.

C. PoND WEB B, MARTIN J. GRAY.

